Tunable Structure and Properties of Segmented Thermoplastic Polyurethanes as a Function of Flexible Segment

Area of Science:

• Polymer Science
• Materials Science
• Organic Chemistry

Background:

• Segmented thermoplastic polyurethanes (PUs) are versatile materials with properties tunable by segment composition.
• Understanding the relationship between microphase separation and material performance is crucial for developing advanced PUs.
• The influence of different macrodiol functional groups on PU properties requires further investigation.

Purpose of the Study:

• To synthesize segmented polyurethanes using macrodiols with varied functional groups (carbonate, ester, ether).
• To investigate the correlation between the degree of microphase separation and the mechanical properties of synthesized PUs.
• To evaluate the stability and retention of tensile properties under various degradation conditions (heat, oil, weather, water).

Main Methods:

• Synthesis of segmented polyurethanes with varying macrodiol segments (1000 and 2000 g/mol) and rigid segments (MDI and 1,4-butanediol).
• Characterization using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), Fourier transform infrared (FTIR), and synchrotron small-angle X-ray scattering (SAXS).
• Assessment of mechanical properties, including tensile properties and hardness shore A, before and after exposure to degradation factors.

Main Results:

• Synthesized PUs exhibited a wide range of microphase separation, directly correlating with mechanical performance.
• Polycarbonate-based macrodiols resulted in the highest degree of phase miscibility among the tested macrodiols.
• These polycarbonate-based PUs showed enhanced tensile properties, hardness, and superior retention of properties under degradation.

Conclusions:

• The functional group of the macrodiol significantly impacts the microphase separation and overall properties of segmented polyurethanes.
• Pure polycarbonate-based macrodiols are highly effective in achieving desirable phase miscibility and mechanical stability in PUs.
• This study provides valuable insights for designing robust thermoplastic polyurethanes for demanding applications.